Andrei, Naoki, Sheila

For the upcoming measurement of the FC backscattering, we need to calibrate the length change of the FC. To do this, we calculated the transfer function from the GS_SL FC control signal [Hz] to FC2 displacement [μm]. We followed the steps in Diagram.png to get to result. The plot bode_all_datasets.png contains all the used datasets.

The resulting transfer function is presented here: Tranfer_func.png (where Result curve is the transfer function). The result was exported to frequency/magnitude/phase dataset and can be found in result_data.txt. The remaining .txt files contain all the used datasets for this calculation.

Assuming that the frequency of the FC resonance shift Δf equal to c/2L corresponds to the FC length change ΔL equal to λ/2. (λ = 532 nm, L = 300 m), then Δf/ΔL = c/(L * λ) = 1.88*10¹²  [Hz/m] = 1.88*10⁶  [Hz/μm]. Multiplying Transfer function by this coefficient will get us the open loop unity gain frequency of 39.4 Hz. Open-loop gain plot (after multiplication) can be found in the following figure: openloop_gain.png.

Sat Jun 29 10:09:48 2024 INFO: Fill completed in 9min 45secs

Lockloss 1403715367

There was ground motion from an earthquake just after the lock loss, but the lock loss itself seemed to be quite sudden. ETMX sees those usual wiggles that we often see.

Robert had just started running HVAC shutdown tests, but this seems very unlikely to be the cause.

TITLE: 06/29 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 153Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 5mph Gusts, 4mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.06 μm/s
QUICK SUMMARY: Locked for 8 hours, calm environment after the earthquake settled down.

TITLE: 06/29 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Observing at 149Mpc
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Two locklosses this shift and recovery was straightforward in both cases. Earthquakes at the end of the shift shook things up, but ultimately H1 rode through. H1 has now been locked and observing for almost 2 hours.

• 03:06 - Lockloss - alog78735
• 04:14 - Observing; mostly automated relock
• 05:35 - Lockloss - alog78737
• 06:29 - Observing; automated relock
• 07:41 - Two incoming EQs from Peru (6.1 and 5.3; likely aftershocks from 7.0 yesterday)
  • SEI_ENV correctly transitioned to EQ mode early from Picket Fence trigger
  • 07:50 - SRM saturation
  • Both R-waves have passed

LOG: No log for this shift.

Lockloss @ 05:35 UTC - link to lockloss tool

End of short lock, no obvious cause. I don't see the same ETMX motion as in the previous lockloss.

Lockloss @ 03:06 UTC - link to lockloss tool

ETMX saw a small hit about a half second before the lockloss.

I made slow (ramp time = 120s) changes of the ITMY ESD bias today during observation mode in order to find a minimum in electronics ground noise coupling, using coherence between DARM and a current clamp on a grounding cable as the figure of merit. This project will continue, but I am done for the day and wanted to get today's times into the alog.

FAMIS 26444, last checked in alog78167

Both BRSs look good. The slight motion of BRS-Y looks to line up with small temperature changes.

FAMIS 26313, last checked in alog78597

CS fan 5 had a slight jump up in noise about a week ago, still well within range.

All other fans largely unchanged from last check and within range.

TITLE: 06/28 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 156Mpc
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY: Two lock reacquisitions, both automated. Robert has been changing some ITM L3 biases while in observing, as approved.
LOG:

• 1601 Observing
• 1656 Lock loss
• 1843 Observing
• 2201-2202 Knocked out of observing while making SDF changes.

TITLE: 06/28 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 8mph Gusts, 5mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.06 μm/s
QUICK SUMMARY: H1 has been locked and observing for over 4 hours.

• Wind and microseism are low
• All other systems nominal

For Robert's tests of changing the ITM L3 bias, I unmonitored a few things to allow him to make changes while we are in observing as approved. These will need to be remonitored at the end of teh weekend. I made the changes while in observing, which didn't knock us out of observing, but I failed to notice that the offset switch was monitored and when Robert changed it we did go out of Observing. Good to know that we can unmonitor channels while in observing.

Unmonitored:

H1:SUS-{ITMX, ITMY}_L3_LOCK_BIAS_{GAIN, TRAMP, OFFSET}

H1:SUS-{ITMX, ITMY}_L3_LOCK_INBIAS

Fri Jun 28 10:09:37 2024 INFO: Fill completed in 9min 33secs

Jordan confirmed a good fill curbside.

While restarting an IOC on cdsioc0 this morning I ran into the IETF GPS leap seconds missing web page issue (reported a year ago in alog71075)

   RuntimeError: Error loading leap file: https://www.ietf.org/timezones/data/leap-seconds.list

The local leapsconds file is managed by the tzdata package, after upgrading this on cdsioc0 the problem was resolved. I checked the leapsecond files are correct on workstations and h1guardian1, it looks like cdsioc0 slipped through.

Jennie W, Sheila

We want to do an OMC scan after unlocked today so we can estimate the mode-matching into the OMC with a hot OM2.

Set SRM, ITMX and ETMs to mis-aligned, IMC locked in guardian.

Ran DC centering loops 3 and 4 to centre on AS_A and AS_B QPDs, then ran OMC ASC to align into OMC_A and OMC_B QPDs. Waited for this to converge spots in centre of QPDs with current nominal QPD offsets.

Made sure that OMC guardian was paused then moved PZT2 slider to bottom of its range on ther OMC_Control screen and ran scan with template:

Did scan but sidebands are still on so can't do visibility measurement easily.

Ref 12-14 are today's scan measurements saved in /ligo/home/jennifer.wright/Documents/OMC_scan/2024_06_27_OMC_scan.xml.

Analysis ongoing.

The first attachment shows spectra (GDS CALIB STRAIN clean, so with calibration corrections and jitter cleaning updated and SRCL FF retuned) with OM2 hot vs cold this week, without squeezing injected.  The shot noise is slightly worse with OM2 hot, while the noise from 20-50Hz does seem slightly better with OM2 hot.  This is not as large of a low frequency improvement as was seen in December.  The next attachment shows the same no squeezing times, but with coherences between PRCL and SRCL and CAL DELTAL.  MICH is not plotted since it's coherence was low in both cases.  This suggests that some of the low frequency noise with OM2 cold could be due to PRCL coherence. 

The optical gain is 0.3% worse with OM2 hot than it was cold (3rd attachment), before the OMC swap we saw a 2% decrease in optical gain when heating OM2 in Decmeber 74916 and last July 71087.  This seems to suggest that there has been a change in the OMC mode matching situation since last time we did this test. 

The last attachment shows our sensitivity (GDS CALIB STRAIN CLEAN) with squeezing injected.  The worse range with OM2 hot can largely be attributed to worse squeezing, the time shown here was right after the PSAMs change this morning 78636 which seems to have improved the range to roughly 155Mpc with cleaning; it's possible that more psams tuning would improve the squeezing further. 

Times used for these comparisons (from Camilla):

• no sqz OM2 hot  cold 24/06/2024 12:18:00 UTC
• no sqz OM2 cold hot 24/06/24 23:52:10 UTC
• sqz with psams adjusted OM2 hot 25/06/2024 13:34:52 UTC
• sqz OM2 cold 16/06/2024 11:51:20 UTC

At the start of commissioning today, before we got to NLN and were having trouble locking the OMC, I took an OMC mode scan when we were locked at 10W.

We manually move the OMC_PZT2_OFFSET to its lowest slider value then run the template which does two 100s ramps of this PZT.

Posting for posterity.

Time of Scan = 15:23:43 UTC

200s length. See template in /ligo/home/jennifer.wright/Documents/OMC_scan/2024_06_06_OMC_Scan_15-23UTC.xml